


The Original Teacher

by Rigen97



Series: Original Teacher [1]
Category: Assassination Classroom
Genre: AU, F/M, Might contain spoiler
Language: English
Status: Completed
Published: 2015-08-11
Updated: 2015-08-11
Packaged: 2018-04-14 05:23:14
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,393
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4552245
Author URL: https://archiveofourown.org/users/Rigen97/pseuds/Rigen97
Summary: <blockquote class="userstuff">
              <p>Korosensei and the entire class E never thought they would see her again. And yet there she was, standing with all her beauty and bloodlust. Yukimura-sensei had returned to class 3-E with murderous intent like none other.</p><p>My first Assassination Classroom fanfic, heck, this is the first time I wrote a fanfic. Enjoy!</p>
            </blockquote>





	The Original Teacher

It's a normal Tuesday, or as normal as it could be in the 3-E of Kunugigaoka Junior High. With Nagisa and Karma went into their mission to infiltrate the joint research data needed to save Korosensei, the rest of the class have to maintain their normal attendance. And because Korosensei is still around, an assassin targeting him is bound to appear at some point.

"Okay, excluding two of our friends in their mission, there are 25 member of the class. Now let's we start the Chemistry class before the Bunsen burner explodes"

"Only Karma-kun would pull out that kind of prank, and since he isn't here, that isn't likely to happen," Kayano said without looking away from her textbook.

"I kinda miss him already" Okuda sighing unconsciously, drawing attention of the entire class.

"Now those are words I never thought I'd hear from Okuda" upon hearing Nakamura's words, Okuda's face turned deep red.

"Please forget everything I've said!" said Okuda with still red face.

"Now let's we ignore her for a second and...."

"Hold up for a second, Korosensei." Karasuma-sensei stands at the class entrance. "I wanted to introduce all of you to your new teacher, well, sort of. You could come in now, Yukimura-san"

And then, standing in front of the class was someone that neither Korosensei nor the entire class 3-E think they would ever met again. Yukimura-sensei, a.k.a Yukimura Aguri, none other than Kayano's elder sister and former homeroom teacher of class 3-E before the arrival of Korosensei.

"Nice to meet you all. I'm Yukimura Aguri, though I think most of you had known about me before. I'll be teaching in this class again, so, I'm looking forward for our next meeting."

"A-Aguri?!?" stunned by what he saw, the former God of Death couldn't think clearly. But before his Mach 20 speed could move even a milimeter, Kayano Kaede a.k.a Yukimura Akari had ran forward and hugged her elder sister.

"Aguri-neechan! Where had you been? I've been looking for you everywhere, I even thought you died! But I should've know better, Aguri-neechan won't leave me, no matter what happen! Please don't leave me again!"

"You've grown quite a bit, Akari-chan. Yeah, I'll never leave your side again."

"Really?"

"Yeah, of course.Now if you allow me, that _thing_ should get back to work, and me too. I have to catch up with your curiculum."

"I believe you have an explanation for all of this, Karasuma-sensei?"

"I hope I have a reasonable explanation, but I'm afraid that that had to wait untill the end of the day"

**** The same day, 16.00 afterschool. Emergency class 3-E meeting minus Kayano Kaede and Yukimura Aguri****

"Now, Karasuma, I believe you owe us an explanation."

"Yes. Yukimura Aguri is the official second human test subject for the tentacle tissue implant experiment that is a spin off from Yanagisawa's antimatter production experiment, the first being Korosesensei and the third being Horibe Itona. Her test was so classified that even I don't know it existed until now."

"So she has the same kind of tentacles I and Kayano once had?" Itona stepped forward

"Yes and no. The tissues implanted inside her body is far more extensive and integrated than you once had, enabling the regenerative properties to fully replace her failing organ. A lot of her internal organ including lungs and liver are ruptured by the tentacle mines, but the same thing that destroyed her had saved her, and in turn made her extremely dangerous."

"Is she here to kill Korosensei? Her comings could jeopardize our plans!" Terasaka yelled.

"I think that's true, since there's no way that guy in white mask would send her with no reason. That guy has some sick and twisted mind, he had no problem using his fiancee as an experiment subject and send her here."

"nurufufu, that Yanagisawa was abusing her even when she was still perfectly human. I won't surprised if she was resurrected for the sole reason of killing me. It's, in fact, a perfect chance for me to apologize to her."

"You've done nothing wrong, Korosensei." Kanzaki stepped closer to Korosensei

"No, I was failed to protect her. I was failed to do something that I could easily done with my body, and yet, I lost sight on the most important person I'd ever know." this is the first time class E saw their invincible Korosensei actually cried. Kanzaki hugged her and patted his back.

"We loved you, Korosensei. And I believe, Yukimura-sensei will forgive you. No matter what she had become, she'll always forgive you."

"well, I would doubt that. Those tentacle tissues will affect her judgment and mental stability, and I bet that Yanagisawa also messing around with her brain."

"Karasuma-sensei! I can't believe you are that dense!" Irina-sensei suddenly burst out

"What? I'm just stating the possibilities!"

"Whatever. I kindly ask you to be quiet for now, Karasuma-sensei."

"I think that's enough for today's emergency meeting. We'll communicate through Ritsu's secured connection. Dismissed!"

After all the student, including Ritsu's bulky CPU left the class, Irina-sensei aproached still silent Karasuma-sensei.

"Wait, Karasuma. I want to talk in private."

"If it's another trick again then I swore...."

"Why'd you so opposed to romance in work?" Irina sensei cut his words.

"There are three reason. First, love could distract me from my main goals. Second, I'd prefer my future partner not knowing about the dark side of the world. Third, in our line of work, romance is as close as you could be to death. You of all people should know this better, Irina."

"So, it's because I'm an assassin? If you ask me, I would happily throw away my career as a hitman, Karasuma."

"It's not only about you, you know? Even if, just if, I actually loved you, I'd live on fear of you only saw me as a target for your assassination. I just can't feel.... Secure, around you. Is a life filled with insecurity could be counted as a happiness?"

"So, was that your answer? Was that your true feeling?"

"My true feeling? Don't mess around." Karasuma-sensei touched Irina-sensei's hair, softly running his hand through. "The truth might not far away from your expectation. But right here, right now, isn't the best time and place for that, Irina." He softly kissed her forehead. "You should be going home too, you wouldn't want to be here alone with the octopus, especially at night."

"Take me home then." Karasuma-sensei smiled at Irina-sensei's feigned naivete.

"Irina, we're both adult, not a highschooler. Even I don't know how I will react to that kind of situation."

"So you still able to react to that kind of things, huh" Irina-sensei gigled

"Of course I am. I'm a man after all. Let's go." Karasuma-sensei walked out of the classroom, followed by Irina-sensei. This time, both of them smiled.

 _If only she knows...._ , Karasuma-sensei thought, _If only she knows how I'm actually feel...._

****The next day, 08.00, thirty minutes before the class started, ****

"Ka-ra-su-ma" Irina-sensei barged in to the Teacher's Office in the class E building, only to got her head smacked by Karasuma-sensei.

"Ugh, this is the actual reason I hated you so much. I just give you a little opening and you become overreactive. Get hold of yourself!"

Yukimura-sensei gigled from across the room "nice to see both of you getting along every day"

"Reality is a harsh mistress, Yukimura-sensei. Irina is hardly 'getting along' with me."

Yukimura-sensei gigled again "It's seems like youre the one who'd been pulling away from her, Karasuma-sensei."

"Of course. There's no telling what she would do if I started giving her more opening." Karasuma-sensei glanced at his watch. "It's almost time for my class to start, so, I'm afraid I have to leave both of you here. Excuse me." Karasuma-sensei walked out from the room, heading to the training field.

"So, have you always been an assassin, Irina-sensei?"

"Yeah, you could say so. I've gone everywhere in my duty as an assassin, but seeing what that octopus have done, I thought I wanted to retire from that world and become a true teacher."

"He was my students after all. I guess that is my legacy."

"What? The talent to turn an assassin into a teacher?"

Yukimura-sensei smiled "Of course. Now, Irina-sensei, if you excuse me, I have a target to kill." as Yukimura-sensei stood up, suddenly the looks on her eyes turned dull, filled with pure hatred and bloodlust that startled even Irina-sensei.

"That kind of pure hatred, I must warn Karasuma about her!"

****PE class, the same day****

"A nice day, isn't it, Korosensei?" Yukimura-sensei sat down besides Korosensei, startling him.

"A-Aguri" _This is bad, I cannot even talk normally beside her_

"I didn't recall we were close enough to call each other by first name, now did we? Our current relationship is an assassin and a target, nothing more and nothing less."

"Yes, Yukimura-sensei. I apologize for my impoliteness."

"Just a reminder, if you dare laid even one of your filthy, _tentacles_ , to my precious sister, then I assure you, you wouldn't have to worry about destroying the earth anymore...." She turned her gaze towards Korosensei "...Because I will destroy every single one of your cells down to last proteins."

"I'll look forward for that, Yukimura-sensei. But before that...." Korosensei stood up "I want to apologize to you"

"Apologize for what?"

"For everything. I apologize for not being able to protect you that night, I apologize for using you as a mean for escape, I apologize for lying to you the whole time I'm in that prison."

"And you expect me to forgive you?"

"No, I don't expect you to forgive me. What I've done is an unforgivable crime. But I honestly wanted the both of us to start over." a momentary silence filled the air between them, tensing every single tentacles in Korosensei's body

Yukimura-sensei sighed "Korosensei, I'd always thought I could see right through you when you still retain your humanity. But then again, you've been lying to me ever since the experiment started. Why'd you thought I'll start trusting you now? For all I know, right now you could be plotting to take out every single person with knowledge about that experiment."

Korosensei shook his head "I grow tired of lying, Yukimura-sensei. And I've done the most forbidden sin for any assassin."

"And what is that 'most forbidden sin', original God of Death?"

"I've fallen in love." Korosensei took a deep breath "I've fallen in love with you, Yukimura Aguri." to his surprise, Yukimura-sensei hugged him

"Please tell me you're not lying." Yukimura-sensei sobbed as tears falling down her cheek to Korosensei's clothes.

"Why would I.... ugh!" Korosensei pulled himself backward as an anti-Korosensei knive destroyed a tentacles.

"You're not lying, so I won't lie either." Yukimura-sensei wiped her tears. "I'd always loved you, Korosensei. Even after what happened that night, I loved you still. But as I stated earlier, now I'm an assassin, and you're my target. _You_ let me die that night, and I won't let my precious students meet the same ending as I had."

"I'm no longer an assassin, Aguri."

"Yeah? Well, but will you capable of protecting them? You cannot even protect me that night! _You left me there to die!_ " another tears rolled down her cheek. She wiped that tears as four huge black tentacles shoot from her back toward Korosensei, piercing his body.

"Korosensei!" Kayano ran forward, only to be stopped by another tentacle from Yukimura-sensei's body.

"Don't get any closer, Akari. I must settle this with this, this _monster_ right here and right now!"

The four tentacles sliced up a great portion of Korosensei's body, forcing him to the absolute defense state "They never told me about this state. What a convenient ability."

"I'm the original after all, I had stuff up my sleeve that human hybrid cannot duplicate."

"And if it's not because of _you_ I won't even become a hybrid right now!"

"And that's exactly why I'm apologizing! I know you won't forgive me. I should know it better than anyone, but...."

"Aguri-neechan!" Kayano snapped through his words "Cut it off! He'd mourn over your death, he had protected me through the last year. Seeing you, the first person to be so important for him, died right in front of his eyes, isn't it enough punishment for him?"

Yukimura-sensei stared with astonishment "What have you done to my little sister?"

"I've done nothing! I loved all your students as much as I loved you!"

"That man is a murderer, Akari. You have heard about his past, about him as the original God of Death."

"And yet he decided to retire, he decided to become our teacher"

"He was treacherous! You cannot believe him!"

"Yes I can, and I have. I trusted him with my life."

Yukimura-sensei retracted all her tentacles. She reached towards Korosensei's absolute defense form, holding him in her hands. "I still cannot forgive you"

"That's to be expected."

"But I cannot stop loving you"

"Neither do I"

"So please, don't let Akari repeat my mistakes. Protect her from the greatest danger of falling in love with the wrong person."

"I'll do my best, Aguri"

"It's a shame we can't kiss in your form, though I doubt I could kiss you in your normal form."

"I love you, Aguri"

"I love you too. Catch, Akari!" Yukimura-sensei threw Korosensei towards her sister, who nervously catched him.

"Uh, about me...." Kayano's face blushed slightly "...I think it's too late"

"What do you mean? Don't tell me, you are already pregnant?"

Kayano hit her sister's stomach. "I'm still a midschooler, idiot!"

"That's hurt, Akari...." Yukimura-sensei hold her stomach, crouching.

"I'm already fallen in love with an assassin, well, sorta"

"Who? That unexplicable yellow ball?"

"You are the only one who could fall in love with this creature!"

"That's before he turned into an obnoxious octopus!" Yukimura-sensei sighed. "So, who is this assassin?"

"An assassin wannabe, actually. His name is Nagisa Shiota"

"He isn't here now?"

"No, he is on a mission."

"Good luck, sister" and with that, Yukimura-sensei walked away from class E. "And oh, one more thing. I'm just taking this day off. I'll return to the class tomorrow. See you, class"

"Good to see her back as a teacher" Korosensei said.

**Author's Note:**

> Soooo, that concludes my first fanfic. Critics and sugestions are welcome. See you later!


End file.
